Soviet Military Power 1986 edition data. For the origin of the data see: John A. Roberts, "The Validity of Soviet Military Power", AD-A227470, 1990, http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA227470
See also: The effects of the atomic bomb on Hiroshima, Japan (the secret U.S. Strategic Bombing Survey report 92, Pacific Theatre) located at: http://archive.org/details/TheEffectsOfTheAtomicBombOnHiroshima